python tests: add msg() utility function (#562)

Most tests need to send a request, process it, then retrieve the reply.
Add a utility function to avoid lots of tedious boilerplate.

Signed-off-by: John Levon <john.levon@nutanix.com>
Reviewed-by: Thanos Makatos <thanos.makatos@nutanix.com>

1 files changed, 3 insertions, 12 deletions

diff --git a/test/py/test_device_get_info.py b/test/py/test_device_get_info.py
index a778604..ea9251b 100644
--- a/test/py/test_device_get_info.py
+++ b/test/py/test_device_get_info.py
@@ -52,28 +52,19 @@ def test_device_get_info():
 
     payload = struct.pack("II", 0, 0)
 
-    hdr = vfio_user_header(VFIO_USER_DEVICE_GET_INFO, size=len(payload))
-    sock.send(hdr + payload)
-    vfu_run_ctx(ctx)
-    get_reply(sock, expect=errno.EINVAL)
+    msg(ctx, sock, VFIO_USER_DEVICE_GET_INFO, payload, expect=errno.EINVAL)
 
     # bad argsz
 
     payload = vfio_user_device_info(argsz=8, flags=0, num_regions=0, num_irqs=0)
 
-    hdr = vfio_user_header(VFIO_USER_DEVICE_GET_INFO, size=len(payload))
-    sock.send(hdr + payload)
-    vfu_run_ctx(ctx)
-    get_reply(sock, expect=errno.EINVAL)
+    msg(ctx, sock, VFIO_USER_DEVICE_GET_INFO, payload, expect=errno.EINVAL)
 
     # valid with larger argsz
 
     payload = vfio_user_device_info(argsz=32, flags=0, num_regions=0, num_irqs=0)
 
-    hdr = vfio_user_header(VFIO_USER_DEVICE_GET_INFO, size=len(payload))
-    sock.send(hdr + payload)
-    vfu_run_ctx(ctx)
-    result = get_reply(sock)
+    result = msg(ctx, sock, VFIO_USER_DEVICE_GET_INFO, payload)
 
     (argsz, flags, num_regions, num_irqs) = struct.unpack("IIII", result)